Pyridazinone compounds and their use as DAAO inhibitors

Abstract

The present invention provides compounds of formula (I) and pharmaceutically acceptable salts thereof, wherein R1 and R2 are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.

The invention claimed is: 
     
       1. A compound selected from 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl}pyridazin-3(2H)-one and pharmaceutically acceptable salts thereof, wherein the compound is in crystalline form. 
     
     
       2. A pharmaceutical composition comprising the compound of  claim 1  and a pharmaceutically acceptable adjuvant, diluent or carrier. 
     
     
       3. A method of preparing a compound selected from 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one and pharmaceutically acceptable salts thereof, wherein the compound is in crystalline form, the method comprising recrystallizing 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one and/or one or more pharmaceutically acceptable salts thereof from a mixture comprising one or more solvents. 
     
     
       4. The method of  claim 3 , wherein the 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one and/or one or more pharmaceutically acceptable salts thereof is recrystallized from a mixture comprising two solvents. 
     
     
       5. The method of  claim 3 , wherein the 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one and/or one or more pharmaceutically acceptable salts thereof is recrystallized from a mixture comprising heptane and ethyl acetate. 
     
     
       6. A compound selected from 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl}pyridazin-3(2H)-one and pharmaceutically acceptable salts thereof that is obtained according to the method of  claim 3 . 
     
     
       7. A compound selected from 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one and pharmaceutically acceptable salts thereof that is obtained according to the method of  claim 5 . 
     
     
       8. A pharmaceutical composition comprising the compound of  claim 7  and a pharmaceutically acceptable adjuvant, diluent, or carrier. 
     
     
       9. The compound of  claim 1 , wherein the compound is 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one. 
     
     
       10. The method of  claim 3 , wherein the compound is 4-hydroxy-6-{2-[4-(trifluoromethyl)phenyl]ethyl} pyridazin-3(2H)-one.